Referring to a Democratic candidate for the Bay Ridge seat, Republican state Sen. Marty Golden described him as “fat boy” when he couldn’t recall his name during a media event with his chief of staff, John Quaglione.

Quiglione is running for the same position, which is being vacated by Councilman Vincent Gentile — who is supporting his own aide, Justin Brannan.

Brannan admits he has to shed a few pounds, but said Golden was out of line in making fun of his weight.

“I’ve been called worse on the schoolyard, but never by a senator. If this is what Senator Golden says about his constituents when a microphone is on, I can only imagine what he says in private,” Brannan said in a statement Friday.

“The senator should spend less time making fat jokes and insulting people, and more time fighting for our public schools and our broken transit system.”

Golden did not immediately returns requests for comment.

According to Campaign Finance Board records, Brannan has raised $99,536 as of May 15 and Quaglione $68,974.

The story was first reported by the Brooklyn Daily, whose reporter — Julianne Cuba — wrote that Golden “warned me not to publish his gaffe, claiming if I did so that I’d never have a sit down with him again.”